From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from stravinsky.debian.org (stravinsky.debian.org [82.195.75.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EDECE40BCB0; Fri, 10 Jul 2026 11:01:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=82.195.75.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783681310; cv=none; b=ostSl8hF1c6RVPpFaHj/sbRY5NDHhWYvPK6HmQLG58z93p1XRMOhyqNIMGOYgPEkkXBWFNnNPNgVfo6+M7Nx1MwJzzANGV7ey/zmB9IDsHuA6yDUtaEA0+DAI5a64iTQLJYf8+P7VyGxok1Vo7xzQiRINAjGxCtdu3T/7barCw8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783681310; c=relaxed/simple; bh=71sj0/+6+Poal/Hsw9DD/HIOLf2nt9C41FsAr+UfcOQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jjiGJKRDIvnNhENMxqqvM0oeL7Lg81PdnJPP7kJE7P21QfNQVjRMP98dR4G1h4JkhnY2lUR3Z7WDKM2viYOR5NWiO4ZvX5mH3KpUiw7knN/Qcm94iM7Dr5aEXtIlUd47F3/va0TrHkEI4uczDEZoMgt4GKsAeqV1tr4JVX7bA5Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org; spf=pass smtp.mailfrom=debian.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b=bAAQTWSy; arc=none smtp.client-ip=82.195.75.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=debian.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b="bAAQTWSy" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=debian.org; s=smtpauto.stravinsky; h=X-Debian-User:In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=RvkH/lWQQy/GTDSrZS8UytO7pjbm+735COICxyv0X08=; b=bAAQTWSyKQzQ8LWsqqbONDNDc+ jLVOOhaGHRZlYboQbs5J1RR8VfMOWAZfWM3D8FqD79mf+KcM2HCCG0l5b9zijWnuKbAcQTYe16q5P OAyLecFJvI/NJi8mkEl7mHE3AvgU/JSRFkwTVE4fooay8yYuwTss8fgeJN+1KXdKvGiBLfzNxek/g kQhzvtOPxtbaoFRj0peX6pTu1+i65+j6BW0g3UzMDrsU1BRqNRzhDDPyXcPlj1VGfTXeGR3HtUkEG XF29qtyIozFpwBp91oisikqUPQWpe9f1dklRUcIprfm5lWbU57GmPO5+MuJOBGO36p7CK5ZTzgZuJ trkMb8FA==; Received: from authenticated-user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1wi8zD-004QqI-2y; Fri, 10 Jul 2026 11:01:40 +0000 Date: Fri, 10 Jul 2026 04:01:35 -0700 From: Breno Leitao To: Paolo Abeni Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Simon Horman , Andrew Lunn , netdev@vger.kernel.org, asantostc@gmail.com, gustavold@gmail.com, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH net-next v2 0/8] netconsole: stop charging netpoll users for netconsole-only data Message-ID: References: <20260702-netconsole_move_more-v2-0-1ebedd921dcb@debian.org> <1bfad1f6-6947-47a4-9dc0-72b4c16fc395@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Debian-User: leitao On Fri, Jul 10, 2026 at 02:46:17AM -0700, Breno Leitao wrote: > On Thu, Jul 09, 2026 at 12:20:24PM +0200, Paolo Abeni wrote: > > Because this initialization happens before acquiring rtnl_lock inside > > netpoll_setup(), enabled_store() can execute INIT_WORK() and > > skb_queue_head_init() simultaneously with the cleanup thread executing > > cancel_work_sync() and skb_queue_purge_reason() on the exact same > > fields. > > I don't think this is a big issue, given worst case scenario, the pool > will not be populated, but this seems a clear regression. Actually, this is a significant issue. We're calling skb_queue_head_init() and INIT_WORK() while those same pointers are being accessed concurrently. The best approach IMO is to move the initialization early (calling INIT_WORK()/skb_queue_head_init() before the race window), making the critical section safe. I'll send an updated series that also addresses another pre-existing bug, bringing the total sashiko issue count to something we can enumerate on our fingers.